Reference may be made to M. S. Kolodesh and W. Cash. Method of and apparatus for separating seeds from a juice/juice sac slurry, U.S. Pat. No. 4,981,220, dated Jan. 1, 1991, wherein the juice slurry/juice sac of citrus fruit collected from the rag separator fed to a seed separator. The seed separator works on the difference in resiliencies or bouncing behaviour of seeds and juice sacs for separation, of seeds. It includes a vibrating stand, inclined perforated bed having a number of channels with distinct ridges and valleys. The perforated bed has a number of upwards ridges arising from the bed's surface. During separation, the residue gets deposited on the bottom end of the bed's upper-side. The vibration of perforated bed caused by its base helps in sending the sacs to collection point. The rising ridges spaced out the clumps of fruit juice sacs during their upward movement to free the seeds present in these sacs. On the basis of different bouncing behaviours, seeds bounce relatively higher than sacs and fell down the bed, collected at closing point and disposed-off. The recovered juice sacs used for adding into prepared fruit product or later mixed with processed juice. The drawbacks are, when the mixture/feed contains fruit pulp and seed in gel form becomes highly sticky in nature, thus making seed separation process inefficient. Further, the pulp gets exposed to the air, as the apparatus is an open chamber, which in turn reacts with air and chemical reactions such as oxidation, polymerization etc. take place, leading to loss of flavour and colour. The application of this invention is only limited to where the difference in bouncing characteristics of the seeds and the fruit sacks are high.
Reference may be made to Marvin Schulman, Richard B. Stevenson. Seeds separating apparatus and method, U.S. Pat. No. 4,609,110, dated Sep. 2, 1986 wherein the apparatus consists of two parallel spaced liberally revolving roller lengthening diagonally across the surface of upper conveyor belt. The roller has smoother surface in contrast to belt (with rougher finish). The fruit sacs move along the rough surface of conveyor belt while separated seeds fall along the smooth surface of the roller. The fruit residue while passing through the gap is subjected to watering onto the surface of conveyor belt. Upstream of the second roller forming a tapered gap with the belt surface was used for the separation of smaller sized seeds or seed particles that are left in the fruit residue. The drawbacks of the said invention are: fragmentation of the seeds due to rolling, which can release undesirable compounds and may impart off-flavour. Inefficient separation of the seeds at the first roller forced inventors to provide a second roller, wherein a liquid spraying device sprays water to detach/separate the seeds from fruit rags. However, the machine does not provide proper drainage/collection of sprayed water, making soggy working space around the machine. This created unhygienic conditions and susceptibility to food contamination.
Reference may be made to William A. Kirk, Citrus seeds separator, U.S. Pat. No. 3,330,410, dated Jul. 11, 1967 wherein seeds are separated from citrus pulp after the extraction of juice. The citrus fruit rag is fed to the hopper, underneath the hopper number of endless conveyor belts were mounted at different altitude on a frame in both directions i.e. lengthwise and transversely. The rag moving on an inclined conveyor belt, discharged from the uppermost portion of the first belt and would fall down on the surface of next lower belt, inclined in opposite direction from the first belt. Falling of the matter from a height causes distress; this resulted in separation of seeds from the pulp. Appropriate motors and gearing system were provided for the movement of belts. The seedless pulp was received over the last conveyor belt and collected separately. The drawbacks of the said invention are: lack of seed collection chamber/point and the seeds rolling off the conveyer belt and dropping on to the ground, resulting in the loss/wastage of seeds. The seeds remained adhered to the pulp due to high moisture and gumminess nature of the pulp, thus leading to inefficient separation of seeds. The machine also required high energy input to move the endless conveyer belts by electric motors and hence, increased the capital investment. Throughput of the machine is very less as the feed needs to be spread over the conveyer belt in a thin layer to separate the seeds from the pulp, thus require huge infrastructure and more energy consumption.
Reference may be made to Xianghua Chen, Method for separating apple seed in apple juice preparation process and centrifugal separator, China Patent Application 1701853A dated: 30 Nov. 2005 wherein apples are fed to the centrifugal separator during juice processing. It consists of centrifuge separators (centrifuge chamber, shaft mounting to two end plates), filter sieve, power machine, transmission gear box, air blower, mechanical dehydration device or horizontal screw-type squeezer or oil presser or vertical screw-type squeezing device, gravity separators etc. The wet material was dewatered by squeezing and then fed to the gravity separator fixed with air blowers. Under the effect of vibrating sieve (three numbers) at specific wind speed, apple seeds were separated along with small quantity of fruit flesh, peels and stems. The drawbacks of the said invention are: the browning of apple pomace due to oxidation—an undesirable character for further value addition. In general, browning results from the exposure of pomace to air thus causing oxidation of polyphenols in the presence of enzyme (polyphenol oxidase) present in the apple fruits. The squeezing device used during dewatering of the wet material causes the crushing/fragmentation of seeds as well, which leads to release of toxic compounds such as cynogenic glycosides. The capital investment is very high as it consists of many electric motors, vibrating sieves for separating the seeds from fruit pulp/skin/stems in different process equipments including centrifuge, air blower, mechanical dehydration device or horizontal screw-type squeezer or oil presser or vertical screw-type squeezing device, gravity separators etc.
Reference may be made to Kaur Devinder, Flotation-cum-sedimentation system for skin and seed separation from tomato pomace, Journal of Food Engineering 71(2005) 341-344 wherein tomato seeds and skin are separated in flotation-cum-sedimentation system consisting of mixing tank, settling and water collecting tanks, seed collecting trays and recirculation pump. The pomace is fed to the mixing tank, agitated and later the mixture is moved to a series of sedimentation tanks for separation of seeds from skin/flesh. The skin/flesh being lighter in weight floated at the top and collected through the upper outlet, whereas seeds settled at the base of the tank and are removed from bottom outlet. The drawbacks of the said invention are that when pulp is exposed to the air, as the mixing tank is an open chamber, it leads to oxidation. It requires huge space to house a number of tanks. The system does not provide single window for seed collection from three settling tanks.
Fruit processing industries are facing a lot of problem in disposal of bio-waste generated during pre and post processing of fruits & vegetables. Besides environmental pollution on dumping sites, it also poses possible health hazards due to growth of undesirable microbes. Even mere dumping of such wastes causes economic losses to the industries. Therefore, value addition of such wastes will not only reduce the environmental pollution, but also give the additional returns to such industries. Efficient separation of seeds will provide advantage of utilization of seedless pomace for preparation of value added products. Commercial apple juice processing units purge pomace as a waste from the factory. The present invention pertains to method and apparatus for the separation of seeds from fruit pulp/slurry/pomace, in general, coming out from food processing industry as a waste and in particular from apple pomace, which essentially consists of skin, pulp, seeds and twigs/pits. Although for many years, it was regarded as a waste; at present apple pomace is being utilized for the production of value added products. Apple pomace comprises 95% skin/flesh, 4% seeds and 1% twigs/stems (Bhushan et al., 2008. Critical Reviews in Biotechnology, 28:285-296). Apple pomace contains 66.4-78.2% (wb) moisture and 9.5-22.0% carbohydrates (Sun et al. 2007 Food Science Technology International 13(2):91-97) and it also contains 26.4% dry matter (DM), 4.0% proteins, 3.6% sugars, 6.8% cellulose, 0.38% ash, 0.42% acid and calcium, 8.7 mg/100 g of wet apple pomace (Vasil'ev et al. 1976. Konservnaya-i-Ovoshchesushil' naya-Promyshlennost. 3:32-34). Polyphenols in apple pomace are: flavanols (catechin, epicatechin, procyanidins), flavonols, hydroxycinnamates and dihydrochalcones (Schieber et al., 2003. Food Sci. Emerg. Technol. 4:99-107). Among flavonoids quercetin and its glycosides are most abundant in plants, including apples. In apple pomace Quercetin-3-O-β-D-galactopyranoside (hyperin), Quercetin-3-O-β-D-glucopyranoside (isoquercitrin), Quercetrin-3-O-β-D-xylopyranoside (reynoutrin), Quercetrin-3-O-α-L-arabinofuranoside (avicularin) and Quercetin-3-O-α-L-rhamnopyranoside (quercitrin) are present in largest quantities (Lu & Foo, 1997. Food Chem. 61(1-2): 29-33).
Apple seeds are generally oval in shape with pointed tip at one end, measuring about 5 mm diameter and 1.5 mm in thickness (depending upon maturity and variety). Apple seeds, the significant part of apple pomace, are rich in fatty oil content (28%) and supplementing proteins (34%). The main component of apple seed (fatty) oil is linoleic acid (ca. 50%) (Lu and Foo, 1997. Food Chem. 61(1-2): 29-33) and also contain significant amount of amygdalin and phloridzin (Lu and Foo, 1998. Food Chemistry, 61(1/2): 29-33) and phosphorous, potassium, magnesium, calcium and iron (Yu et. al., 2007. International Journal of Food Engineering, 3(5) Article12). The metabolism of amygdalin produces hydrogen cyanide, a potent toxin. β-Glucosidase, one of the enzymes that are present in the human intestine, catalyse the release of cyanide from amygdalin leads to an unpredictable and potentially lethal toxicity, when amygdalin is taken orally (Newton et. al., 1981. West. J. Med. 134 (2): 97-103). Injection of purified amygdalin can cause sewer toxicity and death due to cyanide (Lerner, 1981. CA Cancer J Clin. 31 (2): 91-95). The seedless apple pomace consisting of flesh, skin etc. can be used potentially for producing value added products such as dietary fiber, protein, pectin, natural antioxidants, pigments and phenolic compounds (Kolodziejczyk et. al., 2007. Pol. J. Food Nutr. Sci. 57: 291-295; Lu and Foo, 2000. Food Chem. 68(1):81-5). It is, therefore, extremely important to develop an economical method and apparatus for effecting rapid and efficient separation of seeds from apple pomace for commercial production of value added products.
At present, the apple pomace is either dumped as landfill or used to some extent for animal feed. Apple pomace is highly nutritious and therefore, its dumping is not only an economical loss, but also a loss of nutritional bioresource. Therefore, efficient utilization of this bio-waste to improve the commercial feasibility of juice processing industries is the need of the hour. Thus the apparatus and the methods mentioned above for the separation of seeds have one or other major drawbacks like improper seed collection point, water drainage system, insufficient separation of seeds from pulp/skin/flesh, release of undesirable compounds due to seeds fragmentation or splitting/crushing, causing seed damage/loss, open seed separation process causes loss of flavor and color due to oxidation through direct air contact, unhygienic separation leads to contamination/degradation, require more attention/manpower during processing, more capital investment, operational cost, less throughput, high space required for infrastructure.
The present invention contemplates a method and device operated in batch and continuous mode designed, fabricated and calibrated to produce a clean, highly efficient, rapid separation of seeds from the apple pomace in an economical manner, that avoid the splitting or fragmentation of the seeds which can otherwise release undesirable cyanogenic glycosides into the extracted apple pomace.
The pressed apple pomace typically comprises of fruit skin cell wall materials and pulp surrounding gelatinous mucilage having apple seeds embedded therein. Therefore, it is quite difficult to separate seeds from the pomace by using traditional straining methods and devices, which inefficiently separate the seeds from skin/flesh, pulp, etc.